Pulp sceeen for papee mills



(No Model.) 4 Sheets-Sheet 1.

P. R. THOM.

PULP SCREEN-FOR PAPER MILL$.

Patented Jan. 20, 1891.

I a'wuambo a I Pi/ &r 12/. 171 /0210. How 1,24 g p (No Model.) r 4Sheets-Sheet 2. P. R. THOM. PULP SCREEN FOR PAPER MILLS.

No. 444,862. Patented Jan. 20., 1891.

P. R. T'HOM.v PULP SCREEN FOR PAPER MILLS.

No. 444,862. Patented Jan. 20, 1891.

(No Model.) 4 Sheets-$11961; 4.

P. R. THOM. PULP SCREEN FOR PAPER MILLS.

No. 444,862 1 Patented Jan. 20, 189.1.

wi/lmxioow g'vwembo c 3 UNITED STATES PATENT QFFICE...

PETER R. THOM, OF APPLETON, VISOONSIN.

PU LP-SCREEN FOR PAPER-MILLS.

SPECIFICATION forming part of Letters Patent No. 444,862, dated January20, 1891. g

' Application filed February 12, 1890- Serial No. 340,180. (No model.) i

To all whom it may concern.-

Be it known that 1, PETER R. THOM, a citizen of the United States ofAmerica, residing at Appleton, in the county of Outagamie, in the Stateof lVisconsin, have invented certain new and useful Improvements inPulp-Screens for Paper-Mills, of which the following is a specification.

After paper has been properly thinned in the mixing-box it is run overscreens and strained through into a vat or vats beneath,in order thatimpurities, lumps, shreds, and sand, or anything which would injure thequality of the paper may be removed. From the vat it 1s drawn off andtaken to the wire.

It has been found desirable in the use of pulp-screens to impart to suchscreens a vertlcal reciprocation, whereby in the upward movement thereis caused a certain suction upon the pulp overlying the screen, and inthe downward movement a sort of perfiation by which the slits in thescreen-plates are cleared of shreds and lumps and the pulp lightened upabove themfor the next upward reciprocation. It has been attempted toobtam such vertical movement by the use of eccentrics or of rockshaftshaving cranks projecting horizontally, or thereabout, at the normal.Whenever an eccentric is used it must be revolved at a high speed togive the proper vibrations. Whenever a rockshaft with its cranks spreadhorizontally is used, it can give but a single complete up-and-downmovement for each oscillation.

The object of my present invention is to keep the screen permanently ina level position'and impart to it a strictly vertical movement,improving the suction and obviating noise, besides obtaining a greatercapacity and much cleaner stock, avoiding the stringsandlumpsthatwerefrequentlypassedthrough by the old machine, andlessening the wear and tear due to the horizontal movement in suchmachine. To this end 1 mount the screens in boxes which slide invertical guideways, and raise them by means of a link movement appliedat the center of each side of the screen, as will be hereinafterdescribed.

In the drawings, Figure 1 represents in side elevation a single screenhaving my improvement applied thereto. Fig. 2 is a side elevation of adouble screen constructed according to my invention; Fig. 3, a top planview of said screen; Fig. 4, an end elevation thereof.

A represents a metal supporting-frame for the superposed vat B, abovewhich is placed the screen C, provided with screen-plates O, as usual inthis class of machines. One or more vertical guide-brackets D arestrongly bolted to the sides of the vat and receive closely-fittingboxes d, in which short pintles from the screen are supported. Theseboxes rest upon springs 61, of rubber or of any suitable construction,and are permitted an upand-down movement within their guides of aboutone-eighth of an inch, carrying the screen with them, but entirelypreventing it from endwise movement.

Mounted in bearings E, near the foot of the 1 frame and centrallybeneath the screen, is a transverse shaft F, having at each end twovertical crank-arms F, in line with each other, of exactly the samelength and vibratin g to each side of the vertical. These crankarms havewrist-pins f, which support links G, also of equal lengths, the upperends being strapped to outsetting journals 9, secured to the sides ofthe screen at the exact longitudinal center thereof.

Now it will be obvious that if the rock-shaft be oscillated a togglemovement will be produced between the cranks and the links, which willresult in alternately raising and lowering the screen in an exactvertical line twice to each oscillation of the rock-shaft, since thecrank-arms will pass the dead-center in their to and fro movement eachtime that the shaft has a full oscillation. There fore to one end of therock -shaft is secured an arm H, having a wrist-pin h at its upper end,which by means of connecting-rod J is coupled with a wrist-pin upon thedisk K, carried by the driving-shaft L. This drivingshaft of course willbe mounted in suitable bearings, and for that purpose is shown asprovided with journals Z; but the bearings themselves have been omittedas unn ecessary to an understanding of this invention. Power may beapplied to this driving-shaft by means of a pulley M, or by any othersuitable means. It will be evident now that when power is so applied therock-shaft at the foot of the frame will be moved and the linksalternately raised and lowered equally at each end of the machine,carrying the screen up and down. In such movement of the screen theelastic seats to its boxes will prevent any wear, shock, or noise, Whilethe guide-brackets .will prevent endwise movement and will keep itperfectly level and true.

hen it is desired to operate two screens at once, each will be mountedupon links borne by cranks and transverse rock-shafts precisely as inthe before-recited manner, and as indicated in Figs. 2, 3, and 4 of thedrawings. The cranks, however,beneath the screen will be connected by acoupling rod orbar N, and an additional transverse rock-shaft 0 will bemounted in bearings 0 and on the same level as the bearings of the othershaft, and to one end of this rock-shaft Will be fixed thebefore-mentioned actuating-arm. This actuating-arm Will be connected bya wrist-pin p, or by an intermediate crank P and Wrist-pin p with thebarwhich couples the operatingcranks beneath the screens, While theupper end of the actuating-arm will, as before, be coupled by aconnecting-rod with the disk upon the driving-shaft, so that when theact-uat-iug-arm is moved motion Will be imparted to both screens atonce.

I claim as my invention 1. The combination, substantially ashereinbefore set forth, of the vat, the pulp-screen, vertical guides forsaid screen at each side thereof and near its ends, a transverserockshaft centrally beneath the screen and provided with verticalcrank-arms at each side of the frame vibrating to each side of thevertical, or, in other words, departing from the dead-center to theright and left, links connecting said cranks to journals from the centerof the screen, and means for oscillating said rock-shaft.

2. The combination, substantially as hereinbefore set forth, of the vat,two or more screens mounted therein, vertical guides for said screens ateach side thereof, transverse rock-shafts centrally beneath each screen,provided with crank-arms at each end, a rod connecting the cranks ofeach rock-shaft at one side of the supporting-frame, links connectingeach crank with the center of the respective screens, and means forreciprocating said rod.

3. The combination, substantially as hereinbefore set forth, of the vat,the superposed screen, the vertical guide-brackets, the elastic cushionstherein, and the boxes sliding in said guide-brackets and carrying thescreen.

4:. The combination, substantially as hereinbefore set forth, ofthe vat,the screen, the vertical guides at each side of the screen, thetransverse rock-shaft centrally beneath the screen, the crank at eachend of the rockshaft, the links connecting said cranks with journalsfrom the center of the screen, the.

actuating-arm fixed to said rock-shaft, the driving-shaft and its disk,and the connecting-rod coupling a Wrist-pin upon said disk with awrist-pin upon the upper end of the actuating-arm. r

PETER R. THOM. lVitnesses:

H. S. HOLBROOK,

O. E. CLARK.

